Method of drying lumber.



PATENTED FEB. 28, 1905.

APPLIOATION FILED NOV. 18,1904.

wilt two tile. 783,868.

ifatented February 28, 19W".-

JAMES S. JARRATF, OF SAVANNAH, tlEOh-(iiii.

lllllETt-llCtD 0F lDHYINGlZ LUlltllBtEl l.

-{SEECIFlCGA.TiEOItT forming part of Letters Patent No. 783,868, datedFebruary 2%, 1905.

Application filed Kai/ember 18, 1904. Serial No. 288,292.

To It Hill/(Nib 77/ 71141.1 cuiljecrnl:

Be itknown that l, JAMES t5. JARnA'r'r, a citizen of the United Statesof America, residing at Savannah, in the county of Chatham and ldtate ofGeorgia, have invented certain new and useful improvements in Methods ofDrying Lumber, of which the following is such a full, clear, and exactdescription as will enable others skilled in the art to which itappertains to make and use the same, reference being had to'theaccompanying drawing, forming a part hereof.

This invention is an improved method of drying lumber; and it consistsin certain novel features hereinafter first fully described and thenparticularly pointed out in the claims.

in drying lumber the great desideratum is to dry the same thoroughlythroughout without causing a cracking or checking of the lamloci-owingto theoutside drying \vhiletheinside remains comparatively green ormoist. Various methods of drying have been tried heretofore in an effortto remove all the sap from the lumber before the outside is dried; butso fa as i. am aware none has proved satisfactory. in my process thelumber is treated with steam, boiling water, and hot air in such mannerthat all the sap is removed from the lumber and the drying of the sameis effected without any cracking or checking of the surface.

in the accompanyingdrawing] have shown a sectional view of an apparatusspeciallyadapted for the operation of my process.

in the drawn'ig, A designates a tank con structed oi; wood or otherinexpensive material having! a water-charnber on all sides to guardagainst the scorchiiug' or bu ruins of the inner wall of the tank whenthe hot blast is being operated.

l) designates a steam-pipe leading from a boiler, the exhaust oi theFil'()llil-(3l1,1'il]fi, or other source of supply, and entering thetank near the top of the same. rVithin the tank the steampipe is'fOl'l'l'lOtl into or provided with a series of branches U, which extenddown to within about six inches of the floor of the tank and therecomn'nmicate with periterated pipes or nozzles l), which permit thesteam to escape into the tank,

E designates a water-pipe leading from any source of supply and enteringthe tank near the top of the same, the steam and water pipes beingprovided with suitable valves 1* to facilitate the control of the flowthrough the same, as will be readily understood.

A tube or pipe G leads from fan or blower and enters the bottom of thetank. The fan or blower will communicate with the furnace of the steamplant, so that when operated it will drive a blast of hot air into thetank; but the blower and the steam plant have notbeen illustrated, asthey may be of the usual construction and adetailed representation ofthe same is not neeessanvto a complete under standing of my invention.

in practicing my process the lumber is piled within the tank above theperforatml ends or nozzles of the steam-pipes with strips between theseveral layers or rows of lumber, so that the drying medium maycirculate freely around all sides of each piece of lumber. 'l.he tank isconstructed with steam and watertight joints, and after the lumber hasbeen piled therein a steam and water tightcover is placed thereon. so asto completely close the tank. The valve in the steam-pipe is thenopened, so that steam will enter the tank and escape against the lumber,so as to open the pores thereof and penetrate the same. When the steamhas opened the pores of the lumber, i. turn on the water, which willescape from the \vatewpipe within the tank and meet the hot steamtherein, with the result that the water is violently agitated and driveninto the pores of the lumber at the same time that it is boiled by thesteam. steam will be forced into the lumber so as to penct ate the depthof the same and dissolve and force therefrom all the sap, gum, and otherdeleterious foreign matter. lifter the hunber has been treated with thisboiling water a su'llicicnt period of time to entirely renun'e all thesap and gums the flow of water is cut off and thewater dischargedthrrnip'h a suitable escape in one side of the tank about one inch abovethe iioor of thesame d'hen the body of water has been disch: "ed, lconnect the steam-pipe with the live-.haun space of the boiler, so as toadmit to t],

.. tank steam as hot The boiling water and cornlenscd TOG and dry aspossible. This live steam will penetrate the lumber and drive therefromthe water left therein to a very great degree. A slight quantity ofmoisture, however, will remain even after this hot dry steam acts on thelumber, as the steam will tend to condense thereon and by reaction holdsome of the water therein. I therefore start the fan or blower shortlyafter admitting the live hot steam to the tank, so as to drive a hot-airblast into the tank against the lumber. This hot-air blast causes anevaporation of the steam and moisture and the laden blastmay escapethrough the water-discharge. Shortly after the blast is started thesteam is cut OH and the blast allowed to play on the lumber until thesurface of the lumber begins to get quite dry, when the steam is againturned on and permitted to condense against the surface of the lumber toprevent the cracking or checking of the same. As soon as the steam hasmoistened the surface of the lumber I again cut it off and permit theblast to again play thereon alone. This alternate supplying and cuttingoff of the steam may be continued until the hot-air blast has removedall the moisture from the inside of the lumber, the repeated moisteni ngof the surface of the lumber preventing the outside of the lumber beingthoroughly dried while the interior is still moist. After the moisturehas been th us removed from the lumber it is removed from the tank.

In the processes heretofore employed for drying lumber the outside wouldbe completely dried, while the inside would be left moist and containinggum. The result was that the outside would contract and cause a crackingand consequent spoiling of the lumber. My process keeps the surfacemoist until the inside is dry and leaves the lumber solid and in goodcondition for the market. The hot-air blast passes over a shallowquantity of water in the bottom of the tank and absorbs just enough ofthe moisture to obviate and then submitting the lumber to a hot-air.

blast.

3. The method of drying lumber which consists in boiling the lumber andthen submitting the lumber alternately to the action of live steam and ahot-air blast repeatedly.

4. The method of drying lumber which consists in submitting the lumbertothe action of steam within a closed tank, then admitting water to thetank while continuing the admission of steam, then discharging thewater, and then submitting the lumber alternately to the action of steamand a hot-air blast.

5. The method of drying lumber which consists in steaming the lumber,then supplying water to the lumber while continuing the steaming actionwhereby the lumber is boiled, then admitting dry steam to the lumber todrive oif the water, then cutting off the dry steam, then admitting anair-blast to the lumher, then discontinuing the air-blast and againadmitting steam, and then discontinuing the admission of steam and againadmitting the air-blast.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

JAMES S. JARRATT. Witnesses:

E. F. HARTFELDER, C. WVEsTHEIM.

